The Ultimate Collector's Series, or UCS, is a LEGO subtheme of Star Wars introduced in 2000 and was meant to be more detailed and aimed at older builders. These Ultimate Collector's Series sets tend to be larger, and more expensive than typical sets.
2006 LEGO Sets
2006 for LEGO was a year of new themes being introduced and a number of well known themes being retired. LEGO in 2006 introduced and discontinued The Avatar: The Last Airbender, introduced the original Batman theme, Exo-Force, Mindstorms NXT, SpongeBob SquarePants, Remote control Trains and Aqua Raiders. However, the following themes were discontinued; Clikits, Vikings. While LEGO Sports was re-introduced in 2006 with a couple Soccer/Football sets.